Okay I'm not saying this isn't false, but how is it that the three of them never had any joint air exercises before?

First, there was the Korean War so the USA was defnitley there, just probably not Japan.

Then China has been flying warplanes around the sea all the time for the geopolitical funni and because they want Taiwan.

Then the USA runs wargames literally all the time. They even invite the smallest third world countries to participate if they want, which many see as a win because they get to gain some experience flying with other nations.

Did SK and Japan just never show up at the same time lol?